If a charge '\(q\)' moves with velocity \(v\), in a region where electric field (\(E\)) and magnetic field (\(B\)) both exist, then force on it is:
1. \(q(\vec{v} \times \vec{B})\)
2. \(q \vec{E}+{q}(\vec{v} \times \vec{B})\)
3. \( q \vec{E}+q(\vec{B} \times \vec{v})\)
4. \(q\vec{B}+{q}(\vec{E} \times \vec{v})\)
An electron having mass 'm' and kinetic energy E enter in a uniform magnetic field B perpendicularly. Its frequency will be:
1.
2.
3.
4.
In the Thomson mass spectrograph where \(\vec{E}\perp\vec{B}\) the velocity of the undeflected electron beam will be:
1. \(\frac{\left| \vec{E}\right|}{\left|\vec{B} \right|}\)
2. \(\vec{E}\times \vec{B}\)
3. \(\frac{\left| \vec{B}\right|}{\left|\vec{E} \right|}\)
4. \(\frac{E^{2}}{B^{2}}\)
The tangent galvanometer is used to measure:
1. Potential difference
2. Current
3. Resistance
4. In measuring the charge
If the number of turns, area, and current through a coil are given by \(n\), \(A\) and \(i\) respectively then its magnetic moment will be:
1. \(niA\)
2. \(n^{2}iA\)
3. \(niA^{2}\)
4. \(\frac{ni}{\sqrt{A}}\)
A long solenoid carrying a current produces a magnetic field \(B\) along its axis.
If the current is doubled and the number of turns per cm is halved, what will be the new value of the magnetic field?
1. \(B/2\)
2. \(B\)
3. \(2B\)
4. \(4B\)
1. | the speed of the particle remains unchanged. |
2. | the direction of the particle remains unchanged. |
3. | the acceleration remains unchanged. |
4. | the velocity remains unchanged. |
To convert a galvanometer into a voltmeter one should connect a:
1. | high resistance in series with the galvanometer. |
2. | low resistance in series with the galvanometer. |
3. | high resistance in parallel with the galvanometer. |
4. | low resistance in parallel with the galvanometer. |
Two identically charged particles A and B initially at rest, are accelerated by a common potential difference V. They enter into a transverse uniform magnetic field B. If they describe a circular path of radii respectively, then their mass ratio is:
1.
2.
3.
4.